Alkylation of hydroxyalkyl and aminoakyl substituted aromatic compounds



United States Patent 3,256,345 ALKYLATION 0F HY DROXYALKYL AND AMINO-ALKYL SUBSTITUTED AROMATIC COMPOUNDS Paul W. Solomon, Bartlesville,Okla., assignor to Phillips Petroleum Company, a corporation of DelawareNo Drawing. Filed Sept. 28, 1962, Ser. No. 227,062 5 Claims. (Cl.260-618) This invention relates to the alkylation of aroma-ticcompounds. In one aspect this invention relates to the free radialalkyl-ation'of aromatic compounds by l-olefins.

It is well known to produce free radicals by the decomposition oforganic peroxides. In my copending application Ser. No. 845,072, filedOctober 8, 1959, and now US. Patent No. 3,086,982, it is disclosed andclaimed that such free radicals are capable of causing the alkylation ofside chains of alkyl esters and alkyl ketones using l-olefins asalkylating agents. The invention of said copending application thusprovides a new process for the preparation of long chain alkyl estersand long chain alkyl ketones, which process is not limited by theavailability of alcohols and acids of correct chain length as are theprocesses of the prior art.

I have now discovered that the side chain of certain substitutedaromatic compounds having a side chain containing at least two adjacentcarbon atoms therein which are adjacent the aromatic nucleus can bealkylated by l-olefins containing from 4 to 18 carbon atoms per moleculein the presence of a free radial initiator. Thus, broadly speaking, thepresent invention resides in alkylating the side chain of certainaromatic compounds (defined hereinafter) having a side chain containingat least two adjacent carbon atoms therein which are adjacent thearomatic nucleus by reacting said aromatic compounds With a l-olefincontaining from 4 to 18 carbon atoms under alkylation conditions in thepresence of a free radical initiator; and in certain alkylated aromaticcompounds produced in accordance with the above alkylation process, andidentified hereinafter.

An object of this invention is to provide a process for alkylatingaromatic compounds. Another object of this invention is to provide aprocess for alkylating a side chain attached to the aromatic nucleus ofan aromatic compound. Still another object of this invention is toprovide new aromatic compounds. Still another object of this inventionis to provide a process for increasing the length of a side chainattached to the aromatic nucleus of an aromatic compound, said sidechain having at least two adjacent carbon atoms therein which areadjacent said aromatic nucleus. Another object of this invention is toprovide a process by which alkyl radicals can be introduced into theside chain attached to the aromatic nucleus of an aromatic compound.Another object of this invention is to provide a process for reacting anaromatic compound with a l-olefin in the presence of a free radicalinitiator to increase the length of a side chain attached to thearomatic nucleus of said compound, said side chain having at least twoadjacent carbon atoms therein which are adjacent said aromatic nucleus.Other aspects, objects, and advantages of the invention will be apparentto those skilled in the art in view of this disclosure.

Thus according to the invention, there is provided an alkylation processwhich comprises reacting an acryclic 1- olefin containing from 4 to 18carbon atoms per molecule with an aromatic compound characterized by theformula wherein: n is an integer of from 1 to 7 inclusive; R is selectedfrom the group consisting of a hydrogen atom and hydroxyl, cyano, -N(R')and radicals wherein each R is selected from the group consisting of ahydrogen atom and alkyl and cycloalkyl radicals containing from 1 to 8carbon atoms inclusive; under alkylating conditions; in the presence ofa free radical initiator; and recovering an alkylated aromatic compoundfrom the resulting reaction mixture.

Further according to the invention there are provided new aromaticcompounds and compositions including:

1-octyl-2-phenylethylamine; l-heXadecyl-Z-phenylethylamine;l-octyl-2-phenylethanol; 2-octyl-2-phenylethanol; a mixture ofl-octyl-Z-phenylethanol and 2-octyl-2-phenylethanol;l-hexadecyl-2-phenylethanol; Z-heXadecyI-Z-phenylethanol; and a mixtureof l-hexadecyl-Z-phenylethanol and 2-hexadecyI-Z-phenylethanol.

Not all aromatic compounds can be alkylated in accordance with theprocess of the invention. It should be particularly noted that the sidechain attached to the aromatic nucleus of the aromatic compound mustcontain at least two adjacent carbon atoms therein which are adjacentsaid aromatic nucleus. Thus, surprisingly, I have found that suchcompounds as toluene, aniline, and benzylamine cannot be alkylated inaccordance with the process of this invention. When it is attempted toalkylate toluene -as in the process of the present invention there isobtained diphenylethane. When an attempt is made to alkylate aniline orbenzylamine in accordance with the process of the invention no reactionoccurs.

Examples of aromatic compounds in accordance with the above generalformula which can be alkylated in accordance with the invention include,among others, the following: phenylethane, l-phenylpropane,l-phenylbutane, l-phenyl-2,Z-dimethylpropane, 1-phenyl-3-methylpentane,

1-phenyl-3,5-dimethylhexane,

3 N,N-diethyl-4-ethyl-6-phenylcaproamide,N,N-din-octyl-3-phenylpropionamide, N-rnethyl-N-cyclohexyl-4-phenylbutyramide, 8-phenylcaprylarnide, andN,N-di-n-octyl-8-phenylcaprylamide.

The l-olefins which can be used as alkylating agents in accordance withthe present invention are acylic l-olefins containing from 4 to 18carbon atoms. As used herein and in the claims, unless otherwisespecified, the term l-olefins includes both normal and branched chainmonoolefinic hydrocarbons in which the double bond is in a terminal orl-sposition. Examples of suitable l-olefins which can be used in thepractice of the invention in clude, among others, the following:l-butene, isobutene, 3-methyl-l-pentene, 2,4-diethyl-1-hexene, l-octene,1- nonene, 3,5,8-trimethyl-l-decene, l-dodecene,4-n-propyll-tetradecene, l-hexadecene and l-octadecene.

As indicated above, the alkylation of the aromatic compounds withl-olefins in accordance with the invention is carried out in thepresence of a free radical initiator. Any suitable free radicalinitiator which decomposes at usable rates under the reaction condiitonsto furnish free radicals can be used in the practice of the invention.Suitable initiators for furnishing free radicals include the organicperoxide, hydroperoxide, and azo compounds which have half-lives in therange of 0.05 to 50, preferably 0.05 to 20, hours under reactionconditions. Said suitable free radical initiators generally will containfrom 4 to 50 carbon atoms per molecule and usually will contain lessthan 20 carbon atoms. Representative examples of suitable free radicalinitiators include, among others, the following: di-tert-butyl peroxide;tert-butyl hydroperoxide; benzoyl peroxide; azobisisobutyronitrile;tert-butylbenzene hydroperoxide; decumyl peroxide; hydroxyheptylperoxide; cyclohexanone peroxide; t-butylperacetate; 'di-t-butyldiperphthalate; t-butyl perbenzoate; methyl ethyl ketone peroxide;p-menthane hydroperoxide; pinane hydroperoxide;2,5-dimethylhexane-2,S-dihydroperoxide; cumene hydroperoxide; and thelike. The dialkyl peroxides disclosed in my said copending applicationcan also be used in the practice of the invention. Di-tert-butylperoxide is the presently most preferred free radical initiator.

The process of the invention can be carried out over relatively wideranges of temperature, pressure, reaction time, etc. depending upon theparticular reactants and free radical initiator employed. However, ingeneral, in the practice of the invention the reaction temperature willbe within the range of from 30 to 300 C., preferably 100 to 150 C. Areaction temperature should not be chosen which is above the criticaltemperature of either of the reactants, i.e., aromatic compound orl-olefin.

Since the half-life .of the free radical initiator is temperaturesensitive, the reaction time ordinarily varies inversely with thereaction temperature. Said reaction time can vary from 0.1 to 100 hoursor more. A range of from 1 to about 50 hours now appears to providesuflicient time for an appreciable reaction to occur. Residual freeradical initiator when present during the separation of the reactionproducts may lead to explosions if in distillation the distillationvessel is taken nearly to dryness. Therefore, in the examples, reactiontimes of about 48 hours were employed to make certain that the peroxidewas completely pyrolyzed.

The decomposition of the .free radical initiator by pyrolysis is notsensitive to pressure. Therefore, essentially the vapor pressure of thereactants constitutes the lower limit on this variable. Inert gas can beused to pressurize the reaction vessel, if desired. The reaction iscarried outin liquid phase and sufficient pressure is maintained on thereaction vessel to maintain the reactants in liquid phase. Usually, thepressure will be within the range of from 0.5 to 50- atmospheres,although higher pressures can be employed if desired.

The ratio or amounts of the reactants and the free radical initiatoremployed can vary appreciably. However,

best results are obtained by using a molar excess of aromatic compoundto the l-olefin. The mol ratio of aromatic compound to l-olefin willgenerally be within the range of from 2 to 20, preferably 5 to 15. Theamount of free radical initiator or supplier present will generally bewithin the range of from 0.5 to 5 mol percent, based on the total molsof aromatic compound and l-olefin present.

Although the reaction mechanisms of the process of the invention has notbeen fully established, the results obtained are consistent with a freeradical chain mechanism.

Numerous variations in operative procedure can be employed. The processof this invention can be carried out as a batch process, for example, bycharging the reactants into a reaction vessel containing an initiator.'Although any suitable charging procedure can be used, the aromaticcompound is generally charged first followed by the 1- olefin and freeradical initiator. Also, if desired, the present process can be carriedout in a continuous manner. Apparatus suitable for carrying out theprocesses of the invention will be known to those skilled in 'the art.Any suitable apparatus can be employed.

It is desirable to keepthe reaction system as free of chain terminatingcomponents as practicable since the reaction appears to be a chainreaction once it is initiated. Such undesirable materials includemercaptans, quinones, and the like. It is highly desirable, therefore,that the feed components or reactants be freed of these materials aswell as other materials which may tend to inhibit the reaction. Any ofthe known means for removing such contaminants can be used. High feedpurity with respect to these undesirable chain terminating componentsproduces higher yields of product based on the initiator.

At the completion of the reaction, the total reaction mixture can besubjected to any suitable known separation procedure, e.g., distillationand extraction, for recovering the alkylated aromatic compound productand unreacted reactants that may be present.

The products of this invention are useful as plasticizers, emulsifiers,and the like. The products of this invention are also useful asintermediates for the preparation of plasticizers, emulsifiers, or pestcombatting agents such as fungicides. The products of the invention arealso useful as intermediates for the preparation of detergents. F orexample, ethylbenzene can be alkylated with a l-olefin containing 12 to14 carbon atoms to increase the length of the side chain on the benzenenucleus and the resultant alkylation product then sulfonated in knownmanner to produce a detergent.

The following examples will serve to further illustrate the invention.However, saidexamples are included herein for illustrative purposes onlyand are not to be construed as unduly limiting the invention.

Example I A run was carried out in which 2-phenylethylamine was reactedwith l-octene in the presence of a free radical initiator according tothe invention.

In this run, 958 grams (7.9 moles) of pre-distilled 2- phenylethylamine(B.P. 199 C.), 143 grams (1.3 moles) of l-octene and 16 grams (0.11mole) of di-tert-butyl peroxide were charged to a flask, and a stream ofprepurified nitrogen was bubbled through the mixture for several minutesto remove the air present. The mixture was then heated to l30 C. andmaintained at this temperature for 48 hours. During the reaction periodthe contents of the flask were stirred by means of a Tefloncoated steelbar and a magnetic stirred. In addition, a slow stream of prepurifiednitrogen was bubbled through the mixture throughout the reaction period.

At the end of the 48 hour reaction period, the reaction mixture wasallowed to cool to room temperature (approx. 25 C.), after which themixture was subjected to fractional distillation. The following tablesummarizes the distillation.

Cut B.P., C. Pressure, Weight,

mm. Hg grams 1 Residue.

Cit

- 6 From the above data Cut C was established to be relatively pure rCaHaCHgCHCaHu.

Cut D was then subjected to analysis as for Cut C. These results aretabulated below.

Cut D Analytical Results Calculated for- 1 Not known. 2 By freezingpoint depression of benzene.

A l-hexadecyl-Z-phenylethylamine. 4

B =N-isoprop ylidene-l-hexadecyl-2-phenylethylamine.

Based on the weight and boiling point of Cuts A and B, approximatelypercent of the l-octene reacted.

Cut C from the above distillation was analyzed and its physicalproperties were also determined.

OUT 0 Physical properties Found Refractive index my 1.5030

Density d6, g./cc. 0.909 Elemetrital Analysis(l-octyl-2-phenylethylamine, weight percen -Ca1culated-- Carbon, 82.4

Hydrogen, 11.6

Nitrogen, 6.0 Found Carbon, 82:3

Hydrogen, 11.

7 Nitrogen, 4.2 (Dumas) 5.2 (by HC104 titration) Calculated Molecularrefraction, 75.9 Molecular Weight, 233 Found Molecular refraction, 76.0Molecular weight, 277, by freezing point depression of benzene.

Benzam-ide, acetamide, and 3,5-dinitrobenzoate derivatives of this cut(Cut C) were then prepared in known manner by reacting portions of saidout with benzoyl chloride, acetyl chloride and 3,5-dinitrobenzoic acid,respectively. In each case, a crystalline material formed which wasrecrystallized from a suitable solvent. In a typical run, 0.01 mole ofCut C, assuming it to be a 1-octyl-Z-phenylethylamine, and 0.01 mole of3,5-dinitrobenzoic acid were reacted in methanol, following which themethanol was evaporated to obtain a residue. This residue was dissolvedin hot benzene, and hexane was added to precipitate the crystals. Thecrystals, M.P. l33-6 C., were then recovered by filtration.

The derivatives were subjected to elemental analysis and compared to thecalculated values for l-octyl-2- phenylethylamine derivatives.

The residue, Cut E, was also subjected to analysis, yielding thefollowing results.

Cut E Calculated For Analytical Results N c 0 H3) 2 [0 1-150 H2C] CazHos11, 3 =l.537l d4 =0.93l g./cc Molecular weight=780L 769 Weight percent 0=85. 3. 84. 3 Weight percent H=1l.l 12.1 Weight percent N=3.l 3. 6

1 By freezing point depression of benzene.

Example II For comparative purposes, it was attempted to react l-octenewith aniline and withbenzylamine -in the presence of di-tert-butylperoxide. The charges for each of these runs was as follows.

ercent Carbon Percent Hydrogen Percent Nitrogen RecrystallizationDerivative M.P., C. Solvent Calcu- Found Calcu- Found Calcu- Found latedlated lated Aeetamide 96-8 Methanol 78. 5 78. 5 10.6 10.6 5.1 4. 9Benzamide 117. 5-8. 5 81. 9 81. 8 9. 2 9.9 4. 2 4. 3 3,5-Dinitrobenzoatel336 Benzene/Hexane 62.0 62. 3 7.0 7.3 9. 4 9. 5

7 In each run the reactants were charged to the flask, degassed withnitrogen and heated to 120-125 C. for 100 hours (under nitrogen). Theprocedure was as described above in the run employing2-phenyletl1ylamine. When the reaction mixture of each run wasdistilled, it was apparent that no alkylation occurred in either run.

Example III Another run was carried out in which 2-phenylethanol wasreacted with l-octene in the presence of di-tertiary- Found: percent C,79.3; percent H, 7.6. Calculated for 2,3-diphenyl-1,4-butanediol:percent C, 79.3; percent H, 7.5.

Cut B analyzed to be approximately 70 percent. Z-phenylethanol and theremainder was assumed to be the same as Cut C. Cut D and Cut B (afterthe solid was removed) were spectrally quite similar to Cut C, theanalysis of which is given below. Cut F and Cut H were similar to Cut G,the analysis of which is given below. Cut C was analyzed as follows.

Cut

- Calculated for A and/or B 1 By boiling point elevation of CaH A1-oetyl-2-phenyl ethanol. B 2-oetyl-2-phenyl ethanol.

butyl peroxide in the same manner as described above in Example I. Theresults of this run and the analysis of the reaction product are setforth below.

The product was a Water-white liquid which gave the following cuts onfractionation:

The high value for the hydroxyl number indicates that some dextro,levo-racemate of the 2,3-diphenyl-1,4-butanediol (hydroxyl No.463,molecular weight242), identified earlier in Cut E, was present. Thiswould Reagents Used Grams Moles also account for the low carbon andhydrogen values.

A 3,5 -dinitr-obenzoate derivative was prepared and was y m 1.023separated into two fractions, J and K. J was a solid ti filiirararnj13:31:31:::::::::::::::--:: 12 it it which when recrystallizedfrom ethanol melted at C. K was an 011.

Infrared analysis revealed fractions J and K were both polynitroaromaticesters. analysis gave the following results.

Elemental Found Calculated for 3,5-dinitrobenzoate of (3H J KCtH5CH(C5Hi7) CHzOH 0r CGH5CH2CHCBH17 Percent 64.5 67.9 64.5 Percent H-6. 7 7. 4 6. 6 Percent N 7. O 5. 6 6. 5

C t B P a C P ht r S The solid derivative, J, confirmed the presence ofconu ressuremm' 1g g am siderable 1- or 2-octyl-2-phenylethanol. Theoily derivative is not that from 2,3-diphenyl-1,4-butanediol as ele--219 740 1106 61-133 mental analysis is not in agreement with this. Itmay 133-135 1 be an impure derivative of the dextro, levo-racemate of135-148 1 3.5 5:) 148-163 1 5. 4 the 1- or 2-octyl-2-phenylethanol. -1631 4.8 20mm 01 m 5 Cut G was analyzed as follows.

230 0. 1 7.3 o t G 1 Distilland transferred to difierent fractionationcolumn having 60 Calculated for A and/0r B better fractionationefficiency.

1 Residue. 0 A B Mass and infrared analyses of the low bOlllIlg materialAnalytical Results gave 946 grams of 2-phenylethanol, 152 grams of OH OH CH0 H l-octene, 16 grams of t-butyl alcohol and traces of ace 6 5 toneand t-butyl peroxide. 65 onncnzonowms 0112011 Based on infrared analysisall the above cuts contained hydroxyl groups. Alkylation took place atboth the alpha and beta carbon atoms. The cuts from E to I containedsmall amounts of carbonyl material.

A few tenths of a gram of a solid separated from Cut E. Said solid wasfiltered off and recrystallized from 1:1 benzene/cyclohexane to yieldlong white needles, M.P. 13940 C. The literature reports that meso-2,3-dipheny1-1,4-butaned-iol melts at 137.58.5 C. Elemental analysisconfirmed that the solid was the diol.

1 By boiling point elevation of C H A 1-hexadeeyl2-phenylethanol. B2-heXadeeyl-2-phenylethano1.

No solid derivatives could be prepared on this cut. However, the abovedata show that this fraction is at least 50 per cent 1- and/or2-hexadecy'l-2-pheny1ethanol with perhaps some tetracosylphenylethanolpresent.

1% Infrared spectra of Cut C, Cut D and said liquid E from Cut Bindicated that they all had the structure c H OH-R Solid derivativescould not be prepared on any of the fractions obtained in this study.Preparations attempted A molecular weight determination by boiling pointele- 5 included various nitrations, oxidations, and formation of vationof benzene on Cut H gave a value of 538. Since picrates, aroylbenzoicacids, sulfonyl chlorides, sulfoninfrared indicated that this cut wasquite similar to Cut G arn1des, and monoand diamines and theiracetylated it is probably a mixture of isomeric derivatives;

H Liquid E from Cut 13 CH5CH2$HC4H49 I Analytical Results Literature andCalculated and Values for 2-phenyldecane GHzOH m =1.4892 n,, =1.4s11, aD=1.4s28. CgHs 110241149 d =0.875 gJGG d =0.858 g./cc. B.P.=13s-146 c. (9m B.P.=144-150 o. (14 mm.). molecular weight 458, and MolarRetraction=72.5 72.1.

Molecular Weight =217 218. OH llgerceng ga n 3.8. ercen l. C H CH2HC2Ha5 and 1 By freezing point depression of benzene.

GHZOH The physical data above indicate that said liquid E Heap, from OutB is preponderantly a 2-phenyldecane with some molecular weight 570' 2,3t-di tphepylaugane 1preisent. Infrared analysis is con- Approximately20 percent of the original l-octene re- 51S en any 66am acted. 1 OUT 0Example IV Analytical Results Literature and Calculated Values Anotherrun was carried out in which ethylbenzene was for hwymmdecane reactedwith l-octene in the presence of di-tertiary-butyl 4892 2D 1 4793 2 1 ta peroxide in the same manner as described above in EX- 21 13 T EI'IIIIIII phenyn'oc a mane) ample I. The results of this run andanalysis of the T 8 Molar Refract1on=l09A 110.0. product are set forthbelow. Molecular Weight, 1=30 Percent C=86.8 Percent H=l2.2 12.8.

' Reagents Used Grams Moles 1 By freezing point depression of benzene.Ethylbenzene 867 From the above data, a phenyloctadecane 'is definitely%-g lPeroxide 8 indicated and with the help of infrared it can be identiuy 40 fied as a 2-pheny-loctadecane. Infrared analysis is consistentwith a mixture of 2-phenyloctade-cane isomers.

CU T D Calculated for- Analytical Results 2-phenyl11exacosane 2,l9diphenyleic0sane 7LD2D=1.4018- d =0.877 g./cc Molar Refractiou=l46 and143, resp 149 144 Molecular Weight =395 442 434 Percent C=87.4 86. 8 88.4 Percent H=l2.0 13.2 11. 6

1 By freezing point depression of benzene.

The product was a water-white liquid which was fractionated as follows:(a plug of t-butyl alcohol which had formed in the condenser of thereaction setup is not included in the products).

Cut B.P., 0. Pressure, Weight, m. Grams CUT A Mass spectrometricanalysis of A showed the presence of 827 grams of ethylbenzene and 141grams of l-octene.

CUT B Out B separated into a liquid, E, and a solid. The solid wasrecrystallized from ethanol to yield 1.8 grams of white needles, M.P.1256 C. Based on infrared analysis this solid wasmeso-2,3-diphenylbutane. Literature melting point for this compound is126-7 C., confirming its identification.

v prises:

reacting one mol of l-octene with from 2 to 20 mols of an aromaticcompound having a side chain attached to a nuclear carbon atom therein,and of the formula 1 l 12 H total mols of said Z-phenylethanol and saidl-octene A G H R present; at a temperature which is les than the critjical temperature of either of said reactants and H within the range offrom 100 to 150 C.; under sufrficient pressure to maintain saidreactants liquid phase; and recovering said hexadecyl-Z-phenylethan01from the resulting reaction mixture. wherein,

n is an integer of from 1 to 7 inclusive; References Cit d b th E i R isselected from the group consisting of hydroxyl 10 UNITED STATES PATENTSand NH groups, at a temperature which isless than the critical tem-2:606:610 11/1953 Efchak 260-668 perature of either of said reactantsand within the 5 7 12/1953 l et a1 260-668 X range of from 100 to 150C.; under a pressure suffi- 217481178 5/1956 Pmes et a1 260658 cient tomaintain said reactants in liquid phase; in 15 3105 1,766 8/1962 Hunteret 260-668 the presence of from 0.5 to 5 mol percent, based on 3,082,2673/1963 Hunter et v 26O668 the total mols of said starting olefin andsaid starting aromatic compound present, of a free radical initia-FOREIGN PATENTS tor having a ha-lf life within the range of from 0.5384,314 11/1932 Great Britain. to 50 hours under said reactionconditions; and re- 20 covering from the resulting reaction mixture aOTHER REFERENCES product aromatic compound wherein said side chain K d tt 1,, Chemical Abstracts, vol. 51, pages has been increased in length.14999 (1957). A FY0958s for Preparing a y -p y Oga-ta, ChemicalAbstracts, vol. 13, page 1709 (1919). ethanol, which Process prises: 25Siegel et al., Jour. Amer. Chem. Soc., vol. 73, pages reacting from 2 to20 mols of Z-phenylethanol with one 323740 (1951),

mol of l-octene; in the presence of from 0.5 to 5 mol percent of areaction initiating material consisting CHARLES B. PARKER, PrimaryExaminer.

essentially of di-tertiary butyl peroxide, based on the ROBERT V HINESAssistant E x aminer

1. 1-HEXADECYL-2-PHENYLETHAROL.